Module 7: Humans in the Critical Zone

Strengths of the Module

There are several activities here. Depending on the students' background, the class size and the class format, it may not be possible to complete all of them. Instructors should adjust the complexity and number of activities to suit their particular contexts.

These units address the five central InTeGrate goals of:

1. Addressing geoscience-related grand challenges facing society by introducing students to the impacts that humans have on Earth's Critical Zone.
2. Developing students' ability to address interdisciplinary problems by examining how human actions affect Critical Zone processes and what measures can be adopted to reduse those impacts.
3. Improving student understanding of the nature and methods of geoscience and developing geoscientific habits of mind by using geospatial web applications to analyze human impacts on the hydrologic cycle and investigating how human actions affect soil resources.
4. Making use of authentic and credible geoscience data through activities that allow them to evaluate human impacts on local hydrology and soil resources.
5. Incorporating systems thinking by assessing peer-written research proposals focused on Critical Zone questions and applications to grand challenges.

• impacts of human-induced land use and ecosystem changes
• impacts of human-induced changes to the hydrologic cycle

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Module Goals

Specific Module Goals

• Students will use observations, models, data analyses, and research proposals to identify and analyze anthropogenic influences on the Critical Zone.

• Students will identify, describe and analyze:

• The complex responses that natural and man-made ecosystems have to human perturbations (e.g., deforestation, agriculture, development)
• Mechanisms that reduce human perturbations on the Critical Zone
• Political, economic and cultural impacts of perturbations in the Critical Zone
• Ways to reduce human perturbations on the critical zone while maintaining or improving economic, political and social conditions using the Model My Watershed application

Specific Module Learning Objectives:

1. Students will further develop scientific and geoscientific habits of mind through geospatial environmental analysis.
2. Students will be able to identify, interpret and develop mediation techniques to address human impacts to the Critical Zone.
3. Students will be able to identify and explain the impacts of various methods of agricultural production on soils.
4. Students will be able to critically examine research proposals and describe how the proposal would address CZ questions and grand challenges.

Linking Unit Content to Overall Course Objectives

Below is a brief outline of examples within each Learning Unit where instructors can find resources that meet the overarching and four primary learning objectives for the whole Critical Zone curriculum:

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Objective 1) Identify grand challenges that face humanity and societies, ways which humans depend upon and alter the Critical Zone, and the potential role for Critical Zone science to offer solutions for these challenges.

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• Unit 7.1: Using Google Maps and the Generic Model from the Model My Watershed application, students will examine how human development on the landscape changes hydrologic pathways.
• Unit 7.2: Students will examine various methods humans use to grow food and how those methods affect Earth's Critical Zone.
• Unit 7.3: Students will assess how well proposed CZO sites are equipped to address at least one grand challenge that faces humanity.

Objective 2) Use and interpret multiple lines of data to explain Critical Zone processes.

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• Unit 7.1: Using Google Maps and the Generic Model from the Model My Watershed application, students will examine how precipitation, land cover, slope, soil texture and relative humidity affect local hydrology.
• Unit 7.2: Students will examine the different ways that humans have tilled the land and how those methods have affected soil in the Critical Zone.
• Unit 7.3: Students will determine if proposed CZOs would collect sufficient measurements to answer their research questions and address grand challenges.

Objective 3) Evaluate how the structure of the Critical Zone influences Critical Zone processes/services.

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• Unit 7.1: Using Google Maps and the Generic Model from the Model My Watershed application, students will evaluate how human activities have affected Critical Zone processes/services and what measures can be applied to address those changes.
• Unit 7.2: Students will evaluate various measures to protect soil resources while maintaining the means to feed human populations.
• Unit 7.3: Students will discuss how proposed CZO sites would investigate CZ processes/services.

Objective 4) Analyze how water, carbon, nutrients, and energy flow through the Critical Zone and drive Critical Zone processes.

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• Unit 7.1: Using Google Maps and the Generic Model from the Model My Watershed, students will examine how water moves across the landscape and how the mobilization of nutrients and the processing of carbon/energy flow is affected by human actions.
• Unit 7.2: Students will examine how various types of agriculture affect the water cycle, soil carbon, and nutrient cycles and what means are available to reduce human impacts from food production.
• Unit 7.3: Students will identify the architecture of a proposed CZO and the main drivers of CZ processes at the site.

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Assessment

Students will work individually and/or in groups (depending on class size) to analyze how development and land use change affect the Critical Zone, and develop plans supported by oral and written reports on how their plans reduced those impacts while minimizing social and economic impacts to communities (Unit 1). Still working in small groups, students will then analyze the impacts of agriculture on the Critical Zone (Unit 2). They will prepare oral and written reports on various agricultural practices, their impacts to Critical Zone processes, and potential changes in those practices that can reduce the impacts on water and soil resources. Finally, students will incorporate skills and knowledge gained throughout the course to engage in a panel review of proposals for new CZO sites, thinking specifically about how their proposed CZ research would address the impact of humans on the CZ.

Although there are rubrics for specific assignments, students' work can also be evaluated using grading rubrics from the Starting Point project's website on Assessment:

• Assessment of Campus Based Projects
• Instructor Rubric for Written Reports

As a final activity for this module and the course, students should participate in a metacognitive exercise where they work in teams or small groups (no more than 3) to discuss how what they have learned in the module has changed their view of the Critical Zone and humans' impacts on it. They should then return to the class and discuss how the module content affected their world view.

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Module Outline

Unit 7.1: Watershed Modeling (Generic Model) (Two 75 min class sessions)

Access to clean, fresh water is necessary for life. Humans rely on either surface water or groundwater to provide this precious resource. However, as humans change the landscape, they often interfere with the natural movement of water and may also adversely affect water quality. This unit will examine human alterations to hydrology in the Critical Zone and methods that can reduce those impacts using the Simple Model from the Model My Watershed application, which is an online hydrologic model that uses land cover, soil texture, and precipitation as inputs to predict how these variables affect the fate of water on the landscape. After using this interactive model, students will research various Best Management Practices (BMPs) and report on their effectiveness and on the appropriate locations where they should be used. They will then use what they have learned to develop plans, using Google maps, for selected areas on their campus with the aim of reducing runoff.

Unit 7.2: Humans and Agriculture in the Critical Zone (One 75 min class session)

Humans not only reside in the Critical Zone, they depend upon the land and water to provide sustenance. Many regions in the United States produce our food. The Central Valley of California provides fruits and vegetables for the entire nation, while the central US grows the grain crops (e.g., wheat and corn) that not only feed livestock but are also used for bread and cereal products. More specialized agriculture such as citrus fruits, apples, and pears may also be grown regionally. This unit will examine how humans affect the soil and water resources in the Critical Zone through food production. In addition, it will discuss farming practices that led to the Dust Bowl in the 1930s. Finally, it will examine emerging efforts to grow food locally such as Community Supported Agriculture (CSAs) and urban gardening programs.

Unit 7.3: Proposal Panel Review (One 75 class session)

Peer review is an important process in determining priorities for scientific research. Students will participate in a panel review of proposals for new Critical Zone Observatories (CZO) and as a class decide on the proposal most worthy of funding. Students will read proposals, craft a detailed review of the merits and limitations of the proposal, and then discuss the proposals during an in-class panel review. Proposals will be evaluated on how well the proposed CZO would help address global challenges and advance Critical Zone science, and the review process will require students to use knowledge gained in previous modules to assess and communicate which proposals meet these goals.

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